There is a strong demand to reduce the size of electronic systems. The size reduction is especially desirable in mobile electronics where space is a premium, but is also desirable in servers that are placed in big data centers since it is important to squeeze as many servers as possible into a fixed-size real estate.
Some of the largest components in electronic systems are voltage regulators (also referred to as power regulators). Voltage regulators often include a large number of bulky off-chip components and are used to deliver voltages to circuits such as integrated chips, including processors, memory devices (e.g., a dynamic read access memory (DRAM)), radio-frequency (RF) chips, WiFi combo chips, and power amplifiers.
To efficiently deliver power, a voltage regulator can use a “buck” topology. Such a regulator is referred to as a buck regulator. A buck regulator transfers charge from a power source to an output load using an inductor. A buck regulator can use power switches to connect/disconnect the inductor to/from different voltages (each at a different point in time), thereby providing an output voltage that is a weighted average of the different voltages. A buck regulator can adjust the output voltage by controlling the amount of time the inductor is coupled to the different voltages.
Unfortunately, a buck regulator is not well suitable for highly integrated electronic systems. The conversion efficiency of a buck regulator depends on the size of the inductor, in particular when the power conversion ratio is high and when the amount of current consumed by the output load is high. Because an inductor can occupy a large area and is bulky to integrate on-die or on-package, existing buck regulators often use a large number of off-chip inductor components. This strategy often requires a large area on the printed circuit board, which in turn increases the size of the electronic device. The challenge is exacerbated as mobile system-on-chips (SoCs) become more complex and need increasingly larger number of voltage domains to be delivered by the voltage regulator.
Accordingly, new voltage regulator circuits are desirable.